A PIONEERING underground heating system that will create a new Bath of the North resort in a remote dale could be a prototype for other UK sites.

Scientists and engineers have been given £461,000 to develop a twin borehole system for the Eastgate renewable energy village, in County Durham, where there are plans to open the country’s first natural spa since the Romans tapped the hot springs at Bath.

The Northern Echo: Graphic showing Eastgate borehole proposal


Newcastle University is leading a team developing the system, which will be used as a prototype at other UK “hotspots”.

Drilling the second borehole will allow warm groundwater to be continually cycled through rocks as deep as 1,000m and will solve problems which have hindered previous attempts to use deepseated hot water.

And once drilling is completed in March, the team say they could go even deeper to find water at boiling point.

Professor Paul Younger, from the university, said: “Water from such depths is twice as salty as seawater, so unless you happen to be on the coast, you can’t let the spent water flow away at surface.

“By re-injecting water using a second borehole we are able to maintain the natural water pressures in the rocks and allow pumping to continue for many decades to come.”

The new grant from the Department of Energy and Climate Change will also prepare an exploration borehole drilled six years ago for longterm pumping service.

Used water will be reintroduced to the granite at about 420m depth, and will heat up again as it flows through a complicated maze of fractures on its way back to the pumping borehole.

“By recycling the hot water through what is essentially a huge central heating system deep underground, we can produce an almost carbonneutral source of energy,”

said Prof Younger.

His Newcastle colleague Professor David Manning said the plan was to build a geothermal prototype that could be used at other UK sites.

He explained: “Water deep underground gets heated by the naturally-occurring lowlevel radiation that is found in all rocks.

“Some rocks are far better at producing heat than others – especially granite of the kind we drilled into at Eastgate.

This makes it one of the country’s hotspots – where water starts warming up quite close to the surface.”

The new twin borehole system is to be analysed by a team of experts which also includes Professor Jon Gluyas from Durham University, and the world-leading energy engineering firm Parsons Brinckerhoff.

The eco village will be unique in the UK because it will demonstrate all five natural renewable energy sources – wind, solar, biomass, hydro and geothermal.

Durham County Council has given planning permission for the development, which will be largely privately financed and could create 350 jobs.

Homes, a hotel, shops, visitor and education centres, a narrow gauge railway mountain biking and toboggan tracks and a rock park are all included in the plans.